Exception - class "external_api" not found on the user preferences web service documentation page

Log in as admin Create a new user Navigate to Users > Permissions > Define roles in site administration Edit the Authenticated user role Allow the "moodle/webservice:createtoken" capability and save Navigate to Server > Web services > Overview in site administration Complete the following: Enable web services Enable protocols (REST) Enable developer documentation Navigate to Server > Web services > External services in site administration Edit Moodle mobile web service and set as enabled Navigate to Server > Web services > Manage tokens in site administration Create token for test user to use Moodle mobile web service Log out Log in as test user Navigate to Preferences from user menu Press Security keys Press Documentation Confirm page loads without exceptions